Referring to FIG. 1, an infrared camera structure of the prior art comprises an outer shell 11, a lens 12, a plurality of infrared emitters 13, an upper light shade 14. The infrared emitters 13 are infrared LEDs arranged around the lens 12. The lens 12 and the infrared emitters 13 are enclosed within the outer shell 11 attached with the upper light shade 14 on the top side thereon. Since a significant amount of infrared emitters 13 are needed in such a conventional device, they occupy the majority of the camera space, therefore contributing significantly to the production cost. Further, the beam intensity of the infrared emitters 13 is so limited that the effective range for the infrared beam is short.
Infrared light source has been widely used in modern society, such as the sensing system of an automatics door and the light source of a surveillance camera. The light emitting diodes (LEDs), being the infrared light sources 13, are each of small volume but weak intensity. To use as a light source, a multitude of LEDs are needed to attain a practical light intensity, which occupy a significant amount of space and therefore increases the production cost. Further, the clustering of LEDs results in heat radiation problem, which in turn causes overheating of the light source and may result in damage of the chips in the LEDs and blurring of the transparent enclosure. Basically, a light source using a closely packed cluster of LEDs would have problems in durability and light intensity, both increasing the cost of using such light sources.
Further, the heat produced in an infrared chip 13 is conducted through metallic frame, without further heat-radiating parts. Therefore, the electric current running within the chip 13 is restricted for the protection of the chip 13. Since the current is proportional to the light intensity, the light intensity is also restricted.